The Gateway
From Tardis Wiki, the free Doctor Who reference
The Gateway was a structure that sat at the intersection between N-Space and E-Space (where the co-coordinates were at zero). It appeared to be the remains of an old castle which might have been constructed by the Tharils. Inside The Gateway were the mirrors, the mirrors were guarded by the Gundun robots, who walked the time winds where humans could not. The Gateway was partially destroyed when Rorvik attempted a backblast with his ship. (DW: Warriors' Gate)